I'm checking if my application is already running or not and it's saying running even if i stopped the application why?

Question

Inside Program.cs i did:

using System;
using System.Collections.Generic;
using System.Linq;
using System.Windows.Forms;
using System.Diagnostics;
using DannyGeneral;

namespace mws
{
    static class Program
    {
        /// <summary>
        /// The main entry point for the application.
        /// </summary>
        [STAThread]
        static void Main()
        {
            try
            {
                if (IsApplicationAlreadyRunning() == true)
                {
                    MessageBox.Show("The application is already running");
                }
                else
                {
                    Application.EnableVisualStyles();
                    Application.SetCompatibleTextRenderingDefault(false);
                    Application.Run(new Form1());
                }
            }
            catch (Exception err)
            {
                Logger.Write("error " + err.ToString());
            }
        }
        static bool IsApplicationAlreadyRunning()
        {
            string proc = Process.GetCurrentProcess().ProcessName;
            Process[] processes = Process.GetProcessesByName(proc);
            if (processes.Length > 1)
            {
                return true;
            }
            else
            {
                return false;
            }
        }
    }
}

I used a breakpoint and even if i closed my program in this from visual studio and i try to run the application again it return true and throw the message that the application is already runnig.

In the breakpoint i saw that the variable proc contain: My Weather Station.vshost

And now i noticed this happen only if i open another copy of my application in a new visual studio window and the application is on another location on another hard disk and i didn't run the application not on any of the visual studios windows.

So why when i have the same application opened twice in visual studio and it's not running it's thinking that it is running ? And even if i close the second visual studio i still see in proc My Weather Station.vshost but this time it return false.

EDIT

I see now that the variable processes contain twice in index 0 and 1 My Weather Station.vshost And if i close the second visual studio it contain only one.

The question is what is this My Weather Station.vshost ? And why it count it as running application if the application is not running ? How can i make this checking better so if i open more copies of my application it will not think the app is running ?

The reason i wanted to open another copy of my application is that the second one is older and i wanted to see some old things i did.

I can change this:

if (processes.Length > 1)

And make it > 10 for example But still i don't understand what is My Weather Station.vshost ? Why it's running in the memory ? And why it's considering it as running application ?

If you are trying to make sure only 1 instance is running try this thread `http://stackoverflow.com/questions/184084/how-to-force-c-sharp-net-app-to-run-only-one-instance-in-windows` — KSdev, Oct 08 '14 at 19:33
possible duplicate of [Prevent application launch if already running](http://stackoverflow.com/questions/18477502/prevent-application-launch-if-already-running) — Dour High Arch, Oct 08 '14 at 19:35
possible duplicate of [Return to an already open application when a user tries to open a new instance](http://stackoverflow.com/questions/94274/return-to-an-already-open-application-when-a-user-tries-to-open-a-new-instance) — Rowland Shaw, Oct 08 '14 at 19:44
Here's what I use - works for me: http://stackoverflow.com/questions/25538524/how-can-i-get-rid-of-an-abandoned-mutex/25538839#25538839 — RenniePet, Oct 08 '14 at 19:45

score 1 · Accepted Answer · edited May 23 '17 at 11:53

It seems you are trying to create a "single instance application". There are several existing solutions published for this. The generally accepted way to do this is to make use of a mutex and see if it is already held, like here: What is the correct way to create a single-instance application?

Additionally, it appears this is a feature already built into windows forms (which based on the references in your example source file, you seem to use). Refer to Prevent application launch if already running

I'm checking if my application is already running or not and it's saying running even if i stopped the application why?

1 Answers1